Method of and means for casting illustrative ingots



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METHOD OF AND MEANS FOR CAST GATHMANN ING- -I LLUS THAT IVE I NGOTS F1106 June) 11. 1926 EMIL GATHIVIANN, OF BALTIMORE, MARYLAND.

METHOD OF AN D MEANS FOR CASTING IJ LLUSTRATIVE INGOTS Tngots are now generally molded to the desired shape for rolling or forging purposes from molten metal teemed or poured into vertical chambered molds having cast iron chamber walls. Large tonnages of these molds are designed and constructed to absorb the heat of the molten metal more rapidly from the lower portion of the form ing ingot than from the upper part thereof in order that the molten metal may crystallize or solidify without porous spots or shrinkage cavities progressively from the lower part of the ingot to the upper portion thereof until solidification of themolten metal is complete. With this kind of solidification, only a relatively small part 'of unsound or porous metal remains at the top of the completed casting or ingot, which can be readily discarded in the conversion of the ingot into blooms, bars, forgings or any desired fabricated product. Such molds are usually formed with mold chambers which are wider at the top than at the bottom in order'to provide a greater volume of metal in the upper portion of the solidifying ingot than in the lower part thereof.

It. is not possible, of course, to visually observe continuously the gradual and progressive crystallization and solidification of the molten metal when ingots are cast in molds where all the mold walls are opaque and usually of metal, but by removing ingots from their moldsat different periods.

after casting, emptying out any remaining molten metal and splitting the solidified walls or skins of the ingot structure, the condition of the ingot at various stages of crystallization has been observed. This 'operation is obviously expensive and can give only an indication of the amount of solidification at certain periods after casting of the ingot. Although theinspection and study of ingots so splithave given considerable valuable data as to the formation of ingot structure during crystallization of the molten metal at various stages of. solidification, the data thus obtainedhave not given a continuous or complete record of the solidification of the molten metal from the initial crystallization to the completely solidified ingot.

It is now well-known that molten paraffin or molten stearine or a mixture of paraflin and stearine, to which camphor and other materials that melt at low temperatures and crystallize during solidification may be casting steel ingots.

Application filed June 11, 1926. Serial No. 115,216.

added, solidify in much the same manner as molten steel in molds having the general characteristics of molds employed for That is to say, when molten parafiin or stearine, or a mixture of these two or similar substances, ,is poured or teemed into a mold of the Gathmann big-end-up type, the material crystallizes gradually from the inner surface of the mold walls and solidification of the molten substance is progressively inward and upward, the greater portion of the ingot thus being completely and uniformly solidified and only a small imperfect piped or porous portion being formed in the top of the molded casting or ingot.

T have mentioned paraffin and stearine as the substances which I preferably employ for illustrative purposes. This is because such substancesare readily available, have a low melting point and crystallize and reduce in volume during solidification in such manner as to form or tend to form a cavity or pipe in the ingot being cast in a manner alike to crystalline metals, such as steel, but other materials of low melting point having these characteristics may be employed.

Having this type of material in mind, T have devised a method of visually observing the gradual and progressive crystallization ofthese low-melting-point substances and means or devices for practicing the method so that by. actually observing the behavior of such substances while being cast and during the entire period of solidification, the

metal of high heat conductivity and at least one vertical -wall of transparent material having the quality of low heat conductivity, such as plate glass. The metal portion of the mold is preferably made of aluminum to provide combined high heat conductivity and also lightness per volume of mold wall,

as lightness is desirable in illustrative de-,

vices of this kind .so that they may be readily moved from place to place. Other metals may obviously be used, but aluminum is preferred for the reason stated. The mold illustrated in the drawing is otherwise constructed in a manner now quite familiar to those versed in the art of casting sound steel ingots, but some modifications are involved in my new mold which will hereinafter be specified.

The accompanying drawings illustrate a mold made in accordance with my invention, and some of the figures of the drawings illustrate the gradual and progressive crystallization and solidification from the bottom upward of the substance being cast at various stages of crystallization of the molten material to the completely solidified ingot.

Figure 1 is a perspective view of my mold Eng shows an ingot therein partially solidi- Figure 2 shows a front elevation of the mold containing the molten substance just after the mold is poured and before any appreciable solidification has commenced.

Figure 3 illustrates a subsequent step Where the material in contact with the mold walls has commenced to crystallize and solidify.

Figures 4 and 5 illustrate subsequent steps in the process of crystallization.

Figure 6 illustrates the appearance of the ingot after the molten material has all crystallized and completely solidified.

Figure 7 shows a vertical section of the mold and ingot on the line 7-7 of Figure 1.

Figure 8 illustrates how a feeder or shrink head casing may be applied to the mold in order to reduce the size or rather depth of the shrinkage cavity or pipe at the top of the lngot.

Figure 9 is a top plan view of the shrink head casing and also illustrates how it may be connected with an extension of the glass front wall of the mold.

As stated, some of the mold walls of my illustrative mold are made of metal having high heat conductivity, such as aluminum, while another wall is made of transparent material, such as glass, having low conductivity or rather high heat insulating properties. Preferably the back and two side walls of the mold a, Z), c are made of metal, such as aluminum, while the front wall d is made of glass.

The mold chamber is wider at the top than at the bottom, gradually increasing in width from the bottom. upward. The two side walls of the mold are preferably thickest at the bottom and gradually decrease in thickness from the bottom upwards. The rear wall of the mold has these same characteristics, as illustrated in Fig. 7. The purpose of this construction is to provide thick mold walls in the lower portion of the mold, which will absorb heat more rapidly from the lower portion of the molten substance than from the upper portion thereof, so that th lower portion of such substance shall be the first to become solidified and the molten material shall so crystallize as to definitely locate the shrinkage cavity or pipe formed during this crystallization and reduction in volume from the molten to the solid at the top of the ingot, in the manner illustrated in Figures 3 to 6 of the drawings.

The transparent glass front wall (Z may be secured to the metal mold walls in any suitable way. Preferably the side walls of the mold are rabbetted at a: as shown and the glass is fitted in the seats thus formed. The glass extends from top to bottom of the mold and may be held in place in any suitable way as by clamps X.

lVhen' the glass is thus attached to the metal mold, it forms the front wall of the mold chamber, which is preferably made long, wide and thin so as to form a slab ingot, as this shape has been found from experiments to be the best for Visual inspcc tion and illustration of the process of crystallization of the molten material to the solidified ingot. l urthermore, inasmuch as the glass Wall of the mold, by reason of its low heat absorptive and heat insulating qualities, conserves the heat of the forming ingot in contact therewith, the molten substance in the mold crystallizes more slowly on the glass front wall (1 of the mold chamber than on the side and rear metallic wall portions thereof, which metallic walls, as stated, are good conductors of heat, so that a liquid portion of the molten mass of the in got is held longer near the transparent front and is thus easily visible and distinguishable, which would not be the case if the liquid portion of the forming ingot solidified at the same rate at the front as at the side and rear walls of the mold. While at times a slight film of crystals of solidification forms on the glass, such film is so thin as not to obscure or obstruct a vision of the progress of the mechanism of solidification. While paraffin alone may be employed for illustrative purposes, I find that a mixture of paraffin and stearine in proportions of about 75 parts parafiin to 25 parts stearine by weight is preferable, as it causes a difference in color or shade between the liquid mass and the solid crystalline portions of the forming ingot. The dendrites or crystalline edges of the solidifying mass are thus more readily discernible from the molten interior portions of the ingot.

The molten substance at a temperature of 130 Fahrenheit and upwards to say 250 Fahrenheit is carefully teemed or poured into the mold chamber until the mold is filled to the desired height, in the manner illustrated in Figure 2. Then the filled mold is allowed to stand and cool at atmospheric temperature, when the molten material will crystallize on the metallic mold walls and solidify, in the manner illustrated in Figures 7 paraffin in my molds.

, front wall 05 may be has been embodied in 3 to 6' of the drawings. The phases of crys tallizati'on and solidification are practically the same as those incident to the solidification of molten metal, such as steel, when.

cooled in cast iron molds, and, therefore, by

- my invention I am enabled to visually observe and determine the progression of crystallization incident to solidification in steel ingot formation;

When using a mold of the kind shown in Figures 1 to 7 withouta feeder casin or 7 shrink head casing, the shrinkage cavit y or pipe at the top of the mold will be somewhat deeper, molten due to the loss in volume of the material to the solidified ingot, than where a feeder casing having all its Walls of heat-insulating material is used.

A feeder casing may be readily applied to the top of the mold in the manner illustrated in Figure 8 of they drawings. lln this figure, F indicates a feeder casing which may be made of any suitable heat-insulating'material, such as glass, porcelain or plaster of paris. It is three-sided, the back and side walls f, 7, 7 being of substantially the same thickness, and the side walls being formed receive the. extended upa feeder casing is used, the depth of the shrinkage cavity at the top of the ingot is materially-further reduced as has been found to be the case in the use of shrink head casings in the forming of metallic ingots such as steel.

By using a feeder or casing of the kind specified, the heat of the molten material is retained for a longer time in the upper portion of the mold and the size of the cavity at the top of the ingot 'When cast is materially reduced. This is Well understood by those engaged in casting steel ingots and the same result is obtained when casting After the ingot has been cast in the mold and all'the molten substance solidified, the

clamps X may be detached and the glass withdrawn from the mold, when the ingot may be readily removed from the mold or separated from the glass, as the case may be.

While my illustrative mold is shown and described as of the big-end-up type, i. e., a mold having its chamber wider at the top than at the bottom, my invention is notlimited to molds of this type, as it may be and many shapes of mold chambers for illustrating the influence of mold design in controlling the character of crystallization and location of the shrinkage cavity in the fully solidified ingot.

This invention is particularly useful in visually demonstrating the fact that the de sign of the mold chamber and of the mold Walls controls the other kinds and kind of shrinkage cavity l formed during solidification of the ingot from the molten mass, although it may ob viously be employed to determine other important factors of solidificationw of molten substances.

By the use of suitable photographic or microphotographic appliances, well-known in the art, my invention maybe used in the production of permanent records for illustrating the formation of crystals from a molten material having the characteristics of the substances previously described. Such photographic films can be projected by motion picture ap aratus timed to speed up the operation of crystallization and solidification.

,1 claim as my invention: 1

1. A device for visually inspecting the cooling and solidification of a crystalline substance from a molten state, consisting of a mold having some of its vertical walls made of materialhaving high heat absorptive qualities and another wall made of trans-- parent material having relatively low heat absorptive qualities.

2. A device for visually inspecting the cooling and solidification of a substance from a molten state, consisting of a mold having some of its vertical walls made of metal and wall made of transparent metal and a vertically extending front wall made of transparent glass removably secured to the metal walls.

4. A device for visually inspecting the cooling and solidification of a substance from a molten state, consisting of a mold having some of its walls made ofmetal and another wall made of glass in combination with a feeder casing made of heat-insulating material applied to the top of the mold- 5. A device for obtaining data relating to solidification through crystallization-- of a substance from a-mplten state, consisting of a vertically extending mold having a rel-- atively thin but wide mold chamber with some of its walls made of metal and another wall made of transparent glass, through whic I during spected.

6. A device for obtaining data relating to the solidification through crystallization of a substance from a molten state, consistipg of a vertically extending mold having a relatively thin but wide mold chamberwith some of its walls made of metal and another wall made of transparent glass, through which the crystallization of the substance during solidification may be photographicaly recorded.

solidification may be visually inthe crystallization of the substance a of glass,

7. The method hereinbetore described oi molding a molten substance for visual inspection purposes, which consists in pouring the substance, while in a molten condition, into a mold having some of its sides made of heat absorbing material and another side Which mold absorbs heat from some of the vertical sides of the molten substance more) rapidly than from another vertical side, the molten substance being brought into contact with heat absorbing metal on some sides and into contact on another side with transparent material having less heat absorptive qualities.

8. The method hereinbefore described of molding a molten substance for visual inspection or photographic record purposes, which consists in pouring a substance while in a molten condition lnl'lx a mold, having some of itssides made of heat absorbing rename material and 'nnother side of glass Which mold absorbs heat from some of the vertical sides of-the substance more rapidly than from another vertical side the molten substance being brought into contact with heat absorbing metal on some sides and into contact on another side with transparent material having less heat absorptive qualities.

9. The method hereinbefore described of making an ingot from a molten substance, which consists in pouring the molten substance into a mold and in absorbing heat more rapidly from someof the vertical sides of the molten substance than from another vertical side Where the cooling of the substance is retarded.

In testimony whereof, l have hereunto subscribed my nanie EMIL GATHMANN. 

